Measuring Fluoride in Water and Wastewater using the Thermo Scientific Orion Dual Star ph/ise Meter Water and Lab Products, Thermo Fisher Scientific Technical Note 502 Key Words Thermo Scientific Orion Dual Star ph/ise meter, fluoride ion selective electrode (ISE), fluoride, wastewater, water Goal This technical note explains how to accurately measure fluoride content in general water and wastewater samples using the Thermo Scientific Orion Dual Star ph/ise dual channel benchtop meter. Introduction Too much or too little fluoride can be harmful to humans and the environment. Precise measurement of fluoride by municipalities, potable water plants and bottled water manufacturers promotes quality water for consumption and helps prevent damage to the environment. Required Equipment Orion Dual Star ph/ise meter with electrode stand (Cat. No. 2115000) Fluoride combination electrode (Cat. No. 9609BNWP) Automatic Temperature Compensation () probe (Cat. No. 927007MD) Stirrer probe (Cat. No. 096019) or magnetic stir plate and bar 1 ppm fluoride standard premixed with Total Ionic Strength Adjustment Buffer (TISAB) II (Cat. No. 040906) 2 ppm fluoride standard premixed with (Cat. No. 040907) solution (Cat. No. 940909) Thermo Scientific Orion Optimum Results A electrode filling solution (Cat. No. 900061) Deionized water 100 ml volumetric flasks 50 ml beakers 50 ml, 25 ml and 15 ml pipettes 50 ml graduated cylinders or 10 ml automatic pipette
2 Fluoride Electrode Setup Note: Add filling solution each day before using the electrode. The filling solution level should be at least one inch above the level of sample to ensure a proper flow rate. The fill hole should always be open when taking measurements. See Figure 1 for labeled electrode components. Calibration Standard Preparation 1. Prepare a 0.5 ppm fluoride standard by pipetting 50 ml of the 1 ppm fluoride standard premixed with (Cat. No. 040906) and 25 ml of the TISAB II solution (Cat. No. 940909) into a 100 ml volumetric flask. Dilute to the mark with deionized water. Mix the solution well. 1. Remove the protective shipping cap from the sensing element and save the cap for storage. 2. Insert the spout of the Optimum Results A bottle into the electrode fill hole, add a small amount of filling solution to the chamber, tip the electrode upsidedown to wet the O-ring and return the electrode to its original, vertical position. 3. Hold the electrode body and use your thumb to push down on the electrode cap to allow a few drops of filling solution to drain out and wet the junction. 1 ppm F - with 50 ml 50 ml of 1 ppm 100 ml volumetric flask H 2 0 25 ml 25 ml of 4. Release the electrode cap and allow the outer sleeve to return to its original position. If the outer sleeve does not return to its original position immediately, check if the O-ring is moist and repeat step 3. 0.5 ppm 5. Add filling solution to the electrode up to the bottom of the electrode fill hole. 0.5 ppm 6. Soak the electrode in the 1 ppm fluoride calibration standard until all of the equipment is ready for use. 2. Using a graduated cylinder or automatic pipette, add of the 0.5 ppm fluoride standard to a 50 ml beaker and label the beaker. Cap Spring Cable 0.5 ppm 0.5 ppm Outer body Filling chamber O-ring Fill hole 3. Using a graduated cylinder or automatic pipette, add each of the 1 ppm fluoride standard and 2 ppm fluoride standard to separate 50 ml beakers and label the beakers. Inner body Reference element Inner cone 1 ppm F - with 1 ppm 2 ppm F - with 2 ppm Figure 1 : Fluoride Electrode Components
Sample Preparation 1. Using a graduated cylinder or pipette, measure and add 15 ml of the sample to a 50 ml beaker and label the beaker. Add 15 ml of to the beaker. Gently stir the sample and to mix the solution. 15 ml of sample 15 ml of Meter Setup Note: It is highly recommended that the EZ Startup menu be completed the first time that the meter is used. The EZ Startup menu sets important meter parameters, such as the displayed language, date and time, measurement mode and read type for each channel, and data output settings. To access the EZ Startup menu from the measurement mode, press the setup key, press the / keys to highlight EZ Startup and press the f2 (select) key. 1. In the measurement mode, press the setup key. 3 Sample 1 Sample 1 or 2. Press the / keys to highlight Channel 1 or Channel 2, depending on which BNC input the fluoride electrode was connected to, and press the f2 (select) key. 2. Repeat step 1 for additional samples. Meter Preparation The Orion Dual Star meter has two BNC, reference and connections. These connections are labeled as Channel 1 or Channel 2 on the ridge above the connections. Channel 2 Channel 1 3. Press the / keys to highlight Measure Mode and highlight ISE and press the f2 (accept) key. Press the / keys to highlight ppm (or mg/l, depending on your preference or method) and press the f2 (accept) key. 4. Press the / keys to highlight Electrode ID and highlight F - and press the f2 (accept) key. BNC Ref. USB Ref. Stirrer Ground Power BNC RS232 5. Press the / keys to highlight Resolution and press the f2 (select) key. Press the / keys to highlight 3 Significant Figures (1.00) and press the f2 (accept) key. 1. Prepare the power adapter by selecting the appropriate wall outlet plug and sliding the plug plate into the groove on the back of the adapter. 2. Connect the power adapter to the meter and then to the wall outlet. See Figure 2. Connect the fluoride electrode to one of the BNC inputs on the meter and note which channel (channel 1 or channel 2) was selected. See Figure 3. Connect the probe to the 8 pin MiniN input on the meter and note which channel was selected. See Figure 4. Connect the stirrer probe to the stir jack input on the meter. See Figure 5. und Ref. Power. wer BNC RS232 Ground Re Stirrer Figure 2 Figure 3 Figure 4 Figure 5 Gro 6. Press the / keys to highlight Temperature Input and highlight 1 or 2, depending on which 8 pin MiniN input the probe was connected to, and press the f2 (accept) key. 7. Press the / keys to highlight Calibration Setup and highlight Autoblank and press the f2 (select) key. Press the / keys to highlight On and press the f2 (accept) key. Verify that the Low Level Stability and Isopotential options are set to Off. Press the f1 (back) key. 8. Press the / keys to highlight Read Type and press the f2 (select) key. Press the / keys to highlight On Ready and press the f2 (select) key. 9. Press the f1 (back) key. 10. Press the / keys to highlight Instrument Parameters and press the f2 (select) key. 11. Press the / keys to highlight Export Data (PC/ Printer/Log) and press the f2 (select) key. Press the / keys to highlight Export Trigger and press the f2 (select) key. Press the / keys to highlight Channel 1 or Channel 2, depending on which BNC input the fluoride electrode was connected to, and press the f2 (accept) key. Press the / keys to highlight Data Log and press the f2 (select) key. Press the / keys to highlight Data Log On/Off and highlight On and press the f2 (accept) key.
4 12. Press the f1 (back) key twice. 13. Press the / keys to highlight Stirrer Speed and highlight 1 and press the f2 (accept) key. Press the f1 (back) key. 7. Press the f2 (next) key to proceed to the next calibration standard. 8. Rinse the fluoride electrode, probe and stirrer probe with deionized water, blot dry and place into the 1 ppm calibration standard. 14. Press the f1 (back) key. The meter will return to the measurement mode. Calibration Procedure 1. Prepare and condition the fluoride electrode. Connect the fluoride electrode, probe and stirrer probe to the meter (note which channel the fluoride electrode is connected to) and place the electrode and probes in the electrode stand. Prepare the 2 ppm, 1 ppm and 0.5 ppm standards. 1 ppm 9. When the electrode and standard are ready, press the f3 (start) key. 2 ppm 0.5 ppm 2. In the measurement mode, press the cal key. 3. Dual channel display only: Press the / keys to highlight Channel 1 or Channel 2 as the channel to calibrate and press the f2 (accept) key. select... Channel 1 Channel 2 Calibratio 1 ppm 4. Rinse the fluoride electrode, probe and stirrer probe with deionized water, blot dry and place into the 0.5 ppm calibration standard. 10. Wait for the concentration value to stop flashing and then use the numeric keypad and the decimal key to enter the concentration of the second standard as 1.00 and press the f2 (accept) key. Ch.1 ppm F _ Accept, or enter standard value P1 0.50 25.0 C Std. 2 = 1.00ppm 11. Press the f2 (next) key to proceed to the next calibration standard. 12. Rinse the electrode, probe and stirrer probe with deionized water, blot dry and place into the 2 ppm calibration standard. 0.5 ppm 2 ppm 5. When the electrode and standard are ready, press the f3 (start) key to begin the calibration. 13. When the electrode and standard are ready, press the f3 (start) key. 6. Wait for the concentration value to stop flashing and then use the numeric keypad and the decimal key to enter the concentration of the first standard as 0.50 and press the f2 (accept) key. Ch.1 ppm F _ Accept, or enter standard value Std. 1 = 0.50 ppm 14. Wait for the concentration value to stop flashing and then use the numeric keypad and the decimal key to enter the concentration of the third standard as 2.00 and press the f2 (accept) key. F Accept, or enter standard value P1 0.50 25.0 C P2 1.00 25.0 C Std. 3 = 2.00ppm
15. Press the f3 (cal done) key. A summary of the calibration will be displayed. The slope should be -54 mv per decade to -65 mv per decade. 5. Repeat steps 2 through 4 for all of the samples. 5 Sample x F - 16. Press the f2 (log/print) key to save and end the calibration and export the calibration data to the calibration log. NO3-6. When all of the samples have been measured, store the equipment. For short term storage between samples and overnight, store the fluoride electrode in the 1 ppm fluoride calibration standard. Store the probe and stirrer probe dry. Sample Measurement Procedure 1. Calibrate the fluoride electrode and meter (note which channel the fluoride electrode is connected to) and make sure that the electrode and probes are in the electrode stand. Prepare the fluoride samples. Sample 1 Sample 2 Sample 3 Sample 4 2. Rinse the fluoride electrode, probe and stirrer probe with deionized water, blot dry and place into the sample. Press the stirrer key to turn on the stirrer probe. Sample 1 3. The meter display will flash stabilizing and then show ready once the measurement is stable. Record the concentration and temperature of the sample when the meter display shows ready. When ready is shown on the display, the meter will export the measurement to the data log. Dual Channel 1 NH3 NH 3 or 1 Single Channel Display Mode / / 4. Press the stirrer key to turn off the stirrer probe. Remove the fluoride electrode, probe and stirrer probe from the sample.
Visit www.thermoscientific.com/water to view the full line of Thermo Scientific Orion products and download product literature, user guides and manuals and software updates. For any questions or technical support, contact your local Technical Sales Representative or our Technical Support Specialists by phone at 1-978-232-6000 or 1-800-225-1480 (US toll-free), or by email at wai.techservbev@thermofisher.com. Ordering Information To purchase an Orion Dual Star meter, electrodes and other related products, please contact your local equipment distributor and reference the part numbers listed below. Product Description Part Number Meter Orion Dual Star ph/ise Dual Channel Benchtop Meter 2115000 Electrodes Solutions Accessories Orion Fluoride Combination Electrode Orion Stainless Steel Temperature Probe 9609BNWP 927007MD Orion 1 ppm Fluoride Standard Premixed with, 475 ml 040906 Orion 2 ppm Fluoride Standard Premixed with, 475 ml 040907 Orion 10 ppm Fluoride Standard Premixed with, 475 ml 040908 Orion Solution, 3.8 L (1 gallon) 940909 Orion Optimum Results A Electrode Filling Solution, 5 x 60 ml 900061 Orion Stirrer Probe 096019 Swing Arm Electrode Stand 090043 Technical Note 502 thermoscientific.com/water 2015 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific and its subsidiaries. Water and Lab Products North America Toll Free: 1-800-225-1480 Tel: 1-978-232-6000 info.water@thermofisher.com TN-FLWATER-E 0615 RevB Germany Tel: (49) 6184-90-6000 info.water.uk@thermofisher.com China Tel: (86) 21-68654588 India Tel: (91) 22-4157-8800 Singapore Tel: (65) 6778-6876 Japan Tel: (81) 045-453-9175 Australia Tel: (613) 9757-4300 In Australia: (1300) 735-295 InfoWaterAU@thermofisher.com